Adjustable screen



April 6, 1943. ci. H, PETERSON ADJUSTABLE SCREEN Filed Jan. 27, 1942 3 Sheets-Sheet l l'ffce fefersaw E 'BJ' wm,

April 6 1943 c. H. PETERsQN 2,315,651

ADJUSTABLE SCREEN Filed Jan. 27, 1942 3 Sheets-Sheet 2 ,y I 11 rentar Patented Apr. 6, 1943 ADJUSTABLE SCREEN Clarence II. Peterson, Oakland, Calif., assigner of fifty per cent to George W. Peterson, Oakland,

Calif.

Application January 27, 1942, Serial No. 428,428

1 Claim.

` consumed in making changes in equipment to take care of various sifting requirements.

Other objects and advantages of the invention will become apparent to the reader of the following description.

In the drawings:

Figure 1 represents a top plan view of the screen.

Figure 2 is a longitudinal sectional view through the screen taken substantially on the line 2 2 of Figure 1.

Figure 3 is a top plan view of the stationary plate ot the screen.

Figure 4 is a fragmentary top plan view of the adjustable plate of the screen.

Figure 5 is a fragmentary top plan view showing the adjustable plate moved to a position ior iine sifting.

Figure 6 is a longitudinal sectional view through the structure as adjusted to the position shown in Figure 5.

Figure 'l is an enlarged fragmentary detailed sectional view through the adjusting means.

Figure 8 is a section on the line 8 8 of Figure 7.

Figure 9 is a sectional view taken substantially on the line 9-9 of Figure 1.

Referring to the drawings wherein like numerals designate like parts, it can be seen that numeral 5 denotes a stationary plate of the sieve which has openings 6 at the edge portion thereof to receive screws, rivets or the like 'I which are disposed into the usual shaker frame (not shown). Thus, this plate 5 is stationarily secured.

l 'I'he plate 5 has slots 'l at the corner portions thereof to receive bolts 8 which extend downwardly through openings in the corner portions of an adjustable plate II. The bolts 8 are equipped with nuts I2.

One end of the stationary plate 5 has a rectangular-shaped opening I2 therein for receiving a yoke I3 ydepending from the adjacent end of the plate I I and this yoke I3 embraces a reduced portion Il of a screw shaft I5 which is feedable through a xed nut I6 depending from the adjacent end of the plate 5. The screw shaft I5 has a polygonal wrench engageable head I'l at its outer ond and carries a nut I8 which is feedable against the yoke I 3 to hold the screw I5 against seliadjustment.

As can be seen in Figure 3, the plate 5 is formed .with a multiplicity of rows of square openings I9 extending obliquely or diagonally across the plate, from one end of the plate to the other and the edge portion of this area oi openings I9 is iilled in with small openings 2U each about one-fourth the area of anyone of the square openings I9.

The plate II is likewise formed with square openings ISa extending obliquely or diagonally across the plate and these openings I8a are approximately the same size as the openings I9. The difference with the arrangement openings of the plate I I with respect to the plate 5, is that at one end of the plate II a string of small quarter size openings 20a are formed, so that when the plate I I is shifted to the right with respect to the plate 5 in Figure 3, the openings Isa will be overlying the inner sections of the plate 5 between the openings I9 with the left endmost openings Il of the plate l overlying the small openings 20a, thus the adjustment, which is shown in Figure 5 takes care of nne sifting.

While the foregoing specification sets forth the invention in specic terms, it is to be understood that numerous ychanges in the shape, size and materials may be resorted to without departing from the spirity and scope of the invention as claimed hereinafter.

Having described the invention, what is claimed as new is:

A screen for use on a shaker assembly comprising an oblong bottom plate adapted to be fixed on said frame, a similarly shaped top plate superposed on said bottom plate for endwise sliding movement longitudinally of the'same, said bottom plate being provided with a rectangular area of squared openings therein arranged in longitudinal and transverse rows with the apertures aligned cornerwise in the rows, said top plate being provided with a similar sized area of similarly arranged openings, and means to slide said top plate into different set positions whereby the openings therein may be variably registered with the openings in the bottom plate to form square screening openings of different sizes, the bottom plate having at one end thereof, a series of groups of smaller openings, said groups being so positioned that each group registers with one of the endmost rows of squared openings oi said upper plate in ,one set-position and each of said smaller openings being of substantially the same size as the screening openings formed by said squared openings when the plates are in said set position.

CLARENCE H. PETERSON. 

